Reply by bobsmyuncle

Try it first with hydrogen peroxide. It’s a mild organic stain remover. I use it to get berry juices out of my Formica counters. I also use it to remove organic stains from upholstery fabrics. After it does its thing, it converts to water and evaporates away.

Oxalic acid has its own dangers and must be removed before you use it for food use. Even sanding an un-neutralized oxalic acid treated wood can cause respiratory problems.